See also: List of individual Radon isotopes (and general data sources).
General data
Name of the isotope:Radon-209m2; Rn-209m2Symbol:209m2Rn or 209m286RnMass number A:209 (= number of nucleons)Atomic number Z:86 (= number of protons)Neutrons N:123Nucleon pairing (Z - N):even - oddNuclear ratio (N/Z ratio):1.4302325581395 (= neutron-proton ratio)Neutron excess (N-Z):37Excitation energy:3636.81(23) keVIsotopic mass:208.990401(11) u (atomic weight of Radon-209m2)Nuclide mass:208.9432288 u (calculated nuclear mass without electrons)Mass excess:-8.94141 MeVMass defect:1.74833642 u (per nucleus)Nuclear binding energy:1628.56488521 MeV (per nucleus) 7.79217648 MeV (average binding energy per nucleon)Half-life:3.0(3) μsDecay constant λ:231049.06018665 s-1Specific activity α:6.657769716943 × 10+26 Bq g-1 1.799397220795 × 10+16 Ci g-1Spin and parity: (nuclear angular momentum)35/2+
Nuclear Isomers
Nuclear isomers or excited states with the activation energy in keV related to the ground state.
The following table shows the atomic nuclei that are isotonic (same neutron number N = 123) and isobaric (same nucleon number A = 209) with Radon-209m2. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.
